This invention relates to locking devices of the kind comprising an enclosure element permanently fixed to an article which is to be locked and a disposable element which is engageable into the enclosure element to lock the device and disengageable from the enclosure element to unlock the device, by force applied to the locking device, the disposable element being broken, deformed or otherwise damaged during disengagemnt so as not to be re-usable.
Such locking devices are commonly used amongst other purposes for the security sealing of envelopes, packages and so forth to prevent, discourage or indicate unauthorized interference with the contents thereof.
Locking devices of the above kind generally necessitate the use of a tool to disengage the disposable element and thereby open the device and the present invention aims to provide a locking device in which no tool is required to unlock it, the only force required being a manual force provided, for example, by the fingers acting directly on the locking device.